Database user and Site fields empty after upgrades

Under the Databases configuration I find that the database info is lacking after upgrading (3.0.5.2). I don't know exactly when this happened - but a couple of these databases were made before the last upgrade. I have also upgraded the mysql version - but it should not affect these fields.

The fields "Server", "Type" and "Database name" (+ "Active") are populated - but i lost the Site connection and the database user. I dont use any other fields.

The databases seems to work without this data.

My main question is if I can populate the fields "Site" and "Database user" without affecting the database in question? The databases are working correctly - its ispconfig that has lacks data.